Phillips, David. "Sidgwick's Metaethics." Sidgwickian Ethics. : Oxford University Press, 2011-11-25. Oxford Scholarship Online. 2012-01-19. Date Accessed 18 May. 2013 <http://www.oxfordscholarship.com/view/10.1093/acprof:oso/9780199778911.001.0001/acprof-9780199778911-chapter-2>.
Phillips, D.(2011-11-25). Sidgwick's Metaethics. In Sidgwickian Ethics. : Oxford University Press. Retrieved 18 May. 2013, from http://www.oxfordscholarship.com/view/10.1093/acprof:oso/9780199778911.001.0001/acprof-9780199778911-chapter-2.
Phillips, David. "Sidgwick's Metaethics." In Sidgwickian Ethics. : Oxford University Press, 2011-11-25. http://www.oxfordscholarship.com/view/10.1093/acprof:oso/9780199778911.001.0001/acprof-9780199778911-chapter-2.
Phillips D. Sidgwick's Metaethics. In: Phillips D. Sidgwickian Ethics. Oxford University Press; 2011. http://www.oxfordscholarship.com/view/10.1093/acprof:oso/9780199778911.001.0001/acprof-9780199778911-chapter-2. Accessed May 18, 2013.